Process of producing filtering material.



UNITED STATES PATENT OFFICE.

KARL ENZIN GER, OF WORMS, GERMANY, ASSIGNOR TO THE FILTER UNDBRAUTECHNISOHE MASCHINEN FABRIK AOTIEN-GESELLSOHAFT, VOR- MALS L. A.ENZINGER, OF SAME PLACE.

PROCESS OF PRODUCING FILTERING MATERIAL.

SPECIFICATION formingpart of Letters Patent No. 665,652, dated January8, 1901.

Application filed August 18, 1900. Serial No. 27,255. (No specimens.)

To all whom it may concern:

Be it known that I, KARL ENZINGER, of Worms, Germany, have invented acertain new and useful Process of Producing a Filtering Material, ofwhich the following is a full, clear, and exact specification.

The subject of the present invention is a new process of manufacturing afiltering material by means of which beer and other liquids can befiltered and sterilized simultaneously.

For producing the filtering material I employ infusorial earth orkieselguhr,with which experiments in this regard have already been made.Formerly, however, the kieselguhr has simply been boiled with acidsolutions and then dried, whereas according to the present process thekieselguhr is treated in an autoclave without being boiled and the moistcharactor of the product is retained.

The process consists in heating the kieselguhr in an aqueous solution oftwenty per cent. hydrochloric acid and one per cent. nitric acid forsome hours in an autoclave at a temperature of about 120 centigrade. Itis then freed from the liquid by filtering or by means of a'centrifugalmachine and afterward washed with water until the acid is removed. Themass is then pressed, and to prevent its drying up is wrapped invegetable parchment. The product thus procured will filter nearly twiceas rapidly as kieselguhr boiled with acid solutions and dried, thisquality being due particularly to the favorable structure of thekieselguhr so obtained. The material produced will float much moreeasily in water and possesses the property of filtering in such a highdegree that not only are liquids freed from all turbidity, but aresterilized through, the bacteria and other mortific agents beingdestroyed.

The moist material packed in vegetable parchment must be dissolved inwater, a considerable quantity of the latter being employed, so that themass is not converted into a paste or viscous liquid, but the watermerely rendered turbid. This cloudy water is passed through afilter-press, the filtering medium of which consists of cloths, fabric,or porous sheets of any suitable kind. By this means the water, renderedturbid by the mass, as above described, is filtered and the filteringmaterial is precipitated in a uniform layer on the filtering-cloths orthe like of the filterpress. The latter is now ready for use forfiltering and sterilizing beer, wine, brandy, or other liquids. Theseliquids pass through the filtering material, which has been deposited onthe cloths or fabric or the like of the press (which merely serve as abase to receive the said material) and in their passage are thoroughlyfiltered and sterilized.

Having thus fully described my invention,

what I claim as new, and desire to secure by Letters Patent, is

1. The process of producing a filtering material, which consists inheating kieselguhr in an aqueous solution of hydrochloric and nitricacids in an autoclave for several hours substantially as described,freeing the product from the liquid, washing said product with water toremove the acid, pressing it to expel superfluous water, andwrappingitin suitable packing to retain its moisture, all substantiallyas herein set forth.

2. The process of producing a filtering material, which consists inheating kieselguhr in an aqueous solution of twenty per cent.hydrochloric acid and one per cent. nitric acid in an autoclave forseveral hours at a temperature of about 120 centigrade, freeing theproduct from liquid, washing said product with water to remove the acid,pressing it to expel superfluous water, and wrapping it in vegetableparchment to retain its moisture, all substantially as herein set forth.

In Witness whereof I have hereunto set my hand in presence of twowitnesses.

KARL ENZINGER.

Witnesses:

JEAN GRUND, RICHARD GUENTHER.

